:candy: A library converting XLS and XLSX files to a list of Java objects based on Apache POI
:toc: macro
:toclevels: 2
= Poiji
:version: v4.6.0
:branch: 4.6.0
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Poiji is a tiny thread-safe Java library that provides one way mapping from Excel sheets to Java classes.
In a way it lets us convert each row of the specified excel data into Java objects.
Poiji uses https://poi.apache.org/[Apache Poi] (the Java API for Microsoft Documents) under the hood to fulfill the mapping process.
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== Getting Started
In your Maven/Gradle project, first add the corresponding dependency:
You can find the latest and earlier development versions including javadoc and source files on https://oss.sonatype.org/content/groups/public/com/github/ozlerhakan/poiji/[Sonatypes OSS repository].
== Usage
Poiji.fromExcel
Structurecom.poiji.bind.Poiji#fromExcel(java.io.File, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.File, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.File, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.File, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.InputStream, com.poiji.exception.PoijiExcelType, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.InputStream, com.poiji.exception.PoijiExcelType, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.InputStream, com.poiji.exception.PoijiExcelType, java.lang.Class
com.poiji.bind.Poiji#fromExcel(java.io.InputStream, com.poiji.exception.PoijiExcelType, java.lang.Class
com.poiji.bind.Poiji#fromExcel(org.apache.poi.ss.usermodel.Sheet, java.lang.Class
com.poiji.bind.Poiji#fromExcel(org.apache.poi.ss.usermodel.Sheet, java.lang.Class
com.poiji.bind.Poiji#fromExcel(org.apache.poi.ss.usermodel.Sheet, java.lang.Class
PoijiOptions.PoijiOptionsBuilder
Structure== Documentation
Here are the list of features with examples that the latest version of Poiji supports.
=== Annotations
Create your object model:
public class Employee {
@ExcelRow <1>
private int rowIndex;
@ExcelCell(0) <2>
private long employeeId; <3>
@ExcelCell(1)
private String name;
@ExcelCell(2)
private String surname;
@ExcelCell(3)
private int age;
@ExcelCell(4)
private boolean single;
@ExcelCellName("emails") <4>
List<String> emails;
@ExcelCell(5)
List<BigDecimal> bills;
//no need getters/setters to map excel cells to fields
<1> Optionally, we can access the index of each row item by using the ExcelRow
annotation. Annotated variable should be of type int
, double
, float
or long
.
<2> A field must be annotated with @ExcelCell
along with its property in order to get the value from the right coordinate in the target excel sheet.
<3> An annotated field can be either protected, private or public modifier. The field may be either of boolean
, int
, long
, float
, double
, or their wrapper classes. You can add a field of java.util.Date
, java.time.LocalDate
, java.time.LocalDateTime
and String
as well.
<4> If one column contains multiple value, you can get them using a List field. A List field can store items which is of type BigDecimal
, Long
, Double
, Float
, Integer
, Boolean
and String
.
This is the excel file (employees.xlsx
) we want to map to a list of Employee
instance:
|===
|ID | NAME |SURNAME |AGE |SINGLE |BILLS | EMAILS
|123923
|Joe
|Doe
|30
|TRUE
|123,10;99.99
|[email protected];[email protected]
|123123
|Sophie
|Derue
|20
|TRUE
|1022
|[email protected];[email protected]
|135923
|Paul
|Raul
|31
|FALSE
|73,25;70
|[email protected];[email protected]
|===
The snippet below shows how to obtain the excel data using Poiji
.
PoijiOptions options = PoijiOptions.PoijiOptionsBuilder.settings()
.addListDelimiter(“;”) <1>
.build();
List
// alternatively
InputStream stream = new FileInputStream(new File(“employees.xls”))
List
<1> By default the delimiter/separator is ,
to split items in a cell. There is an option to change this behavior. Since we use ;
between items, we need to tell Poiji to use ;
as a separator.
By default, Poiji ignores the header row of the excel data. If you want to ignore the first row of data, you need to use PoijiOptions
.
By default, Poiji selects the first sheet of an excel file. You can override this behaviour like below:
=== Prefer Default Value
If you want a date field to return null
rather than a default date, use PoijiOptionsBuilder
with the preferNullOverDefault
method as follows:
java.util.Date
, Float
, Double
, Integer
, Long
or String
will have a null
value.=== Sheet Name Option
Poiji allows specifying the sheet name using annotation
@ExcelSheet(“Sheet2”) (1)
public class Student {
@ExcelCell(0)
private String name;
@ExcelCell(1)
private String id;
@ExcelCell(2)
private String phone;
@Override
public String toString() {
return "Student {" +
" name=" + name +
", id=" + id + "'" +
", phone='" + phone + "'" +
'}';
}
<1> With the ExcelSheet
annotation we are configuring the name of the sheet to read data from. The other sheets will be ignored.
=== Protected Excels
Consider that your excel file is protected with a password, you can define the password via PoijiOptionsBuilder
to read rows:
=== Annotation ExcelCellName
Using ExcelCellName
, we can read the values by column names directly.
public class Person {
@ExcelCellName("Name") <1>
protected String name;
@ExcelCellName("Address")
protected String address;
@ExcelCellName("Age")
protected int age;
@ExcelCellName("Email")
protected String email;
@ExcelCellName(value = "", expression = "Surname|Second name") <2>
private String surname;
name
of the column for which the corresponding value is looked. By default, @ExcelCellName
is case-sensitive and the excel file should’t contain duplicated column names. However, you can manipulate this feature using PoijiOptionsBuilder#caseInsensitive(boolean)
and you can ignore white spaces using PoijiOptionsBuilder#ignoreWhitespaces(boolean)
.expression
leaving the column name
empty.For example, here is the excel (person.xls
) file we want to use:
|===
| Name |Address |Age |Email |Surname
|Joe
|San Francisco, CA
|30
|[email protected]
|Doe
|Sophie
|Costa Mesa, CA
|20
|[email protected]
|Doe
|===
Given that the first column always stands for the names of people, you’re able to combine the ExcelCell
annotation with ExcelCellName
in your object model:
public class Person {
@ExcelCell(0)
protected String name;
@ExcelCellName("Address")
protected String address;
@ExcelCellName("Age")
protected int age;
@ExcelCellName("Email")
protected String email;
=== Super Class Inheritance
Your object model may be derived from a super class:
public abstract class Vehicle {
@ExcelCell(0)
protected String name;
@ExcelCell(1)
protected int year;
}
public class Car extends Vehicle {
@ExcelCell(2)
private int nOfSeats;
and you want to map the table (car.xlsx
) below to Car objects:
|===
|NAME |YEAR |SEATS
|Honda Civic
|2017
|4
|Chevrolet Corvette
|2017
|2
|===
Using Poiji, you can map the annotated field(s) of super class(es) of the target class like so:
=== Annotation ExcelCellsJoinedByName
Using ExcelCellsJoinedByName
we can read columns which name meets same regular expression. Values will be combined as a multi valued map.
Please pay attention the variable must be initialized explicitly.
public class Album {
@ExcelCellsJoinedByName(expression = "Artist") <1>
private MultiValuedMap<String, String> artists = new ArrayListValuedHashMap<>();
@ExcelCellsJoinedByName(expression = "Track[0-9]+") <2>
private MultiValuedMap<String, String> tracks = new ArrayListValuedHashMap<>();
name
Artist.name
Track1, Track2, Track3, etc.For example, here is the excel (album.xls
) file we want to use:
|===
| Artist |Artist |Artist |Track1 |Track2
|Michael Jackson
|Lionel Richie
|Stevie Wonder
|We are the World
|We are the World (instrumental)
|artist 1
|artist 1
|artist 1
|track 1
|track 1
|===
Json presentation for album1
will be as follows
=== ExcelCellRange Annotation
Consider you have a table like below:
|===
.2+|No. 5+|Personal Information 3+| Credit Card Information
|Name | Age | City | State | Zip Code | Card Type | Last 4 Digits | Expiration Date
|1
|John Doe
|21
|Vienna
|Virginia
|22349
|VISA
|1234
|Jan-21
|2
|Jane Doe
|28
|Greenbelt
|Maryland
|20993
|MasterCard
|2345
|Jun-22
|3
|Paul Ryan
|19
|Alexandria
|Virginia
|22312
|JCB
|4567
|Oct-24
|===
The ExcelCellRange
annotation lets us aggregate a range of information in one object model. In this case, we collect the data in PersonCreditInfo
plus details of the person in PersonInfo
and for the credit card in CardInfo
:
public class PersonCreditInfo {
@ExcelCellName("No.")
private Integer no;
@ExcelCellRange
private PersonInfo personInfo;
@ExcelCellRange
private CardInfo cardInfo;
public static class PersonInfo {
@ExcelCellName("Name")
private String name;
@ExcelCellName("Age")
private Integer age;
@ExcelCellName("City")
private String city;
@ExcelCellName("State")
private String state;
@ExcelCellName("Zip Code")
private String zipCode;
}
public static class CardInfo {
@ExcelCellName("Card Type")
private String type;
@ExcelCellName("Last 4 Digits")
private String last4Digits;
@ExcelCellName("Expiration Date")
private String expirationDate;
}
Using the conventional way, we can retrieve the data using Poiji.fromExcel
:
PoijiOptions options = PoijiOptions.PoijiOptionsBuilder.settings().headerCount(2).build();
List
=== Support Consumer Interface
Poiji supports Consumer Interface. As https://github.com/ozlerhakan/poiji/pull/39#issuecomment-409521808[@fmarazita] explained the usage, there are several benefits of having a Consumer:
For example, we have a Calculation entity class and want to insert each row into a database while retrieving:
class Calculation {
@ExcelCell(0)
String name
@ExcelCell(1)
int a
@ExcelCell(2)
int b
public int getA(){
return a;
}
public int getB(){
return b;
}
public int getName(){
return name;
}
File fileCalculation = new File(example.xlsx);
PoijiOptions options = PoijiOptionsBuilder.settings().sheetIndex(1).build();
Poiji.fromExcel(fileCalculation, Calculation.class, options, this::dbInsertion);
=== Custom Casting Implementation
You can create your own casting implementation without relying on the default Poiji casting configuration using the Casting
interface.
public class MyCasting implements Casting {
@Override
public Object castValue(Class<?> fieldType, String value, PoijiOptions options) {
return value.trim();
}
}
public class Person {
@ExcelCell(0)
protected String employeeId;
@ExcelCell(1)
protected String name;
@ExcelCell(2)
protected String surname;
Then you can add your custom implementation with the withCasting
method:
PoijiOptions options = PoijiOptions.PoijiOptionsBuilder.settings()
.withCasting(new MyCasting())
.build();
=== Parse UnknownCells
You can annotate a Map<String, String>
with @ExcelUnknownCells
to parse all entries,
which are not mapped in any other way (for example by index or by name).
This is our object model:
public class MusicTrack {
@ExcelCellName("ID")
private String employeeId;
@ExcelCellName("AUTHOR")
private String author;
@ExcelCellName("NAME")
private String name;
@ExcelUnknownCells
private Map<String, String> unknownCells;
This is the excel file we want to parse:
|===
|ID | AUTHOR |NAME |ENCODING |BITRATE
|123923
|Joe Doe
|The example song
|mp3
|256
|56437
|Jane Doe
|The random song
|flac
|1500
|===
The object corresponding to the first row of the excel sheet then has a map with {ENCODING=mp3, BITRATE=256}
and the one for the second row has {ENCODING=flac, BITRATE=1500}
.
Note that If you use the PoijiOptionsBuilder#caseInsensitive(true)
option, the ExcelUnknownCells map will be parsed with lowercase.
=== Optional Mandatory Headers and Cells
As of 4.0.0, @ExcelCellName
and @ExcelCell
are given to provide mandatoryHeader
and mandatoryCell
fields, meaning we can be more specific by declaring rules in headers or cells or both in excel files. mandatoryHeader
expects the labeled excel column exists in a given excel file, while mandatoryCell
looks into the values of the mentioned header/column. If any of the options is active and your excel breaks the rule, either a HeaderMissingException
or PoijiMultiRowException
will be thrown accordingly.
// default behavior
@ExcelCellName(value = “COLUMN_NAME”, mandatoryHeader = false, mandatoryCell = false)
String fieldName;
mandatoryHeader
field is compatible with XLS and XLSX files.mandatoryCell
field works only with XLS files and Sheet
instances. XLS workbooks are opened with RETURN_BLANK_AS_NULL
missing cell policy. If passing a Sheet
instance it is up for the caller to make sure the missing cell policy of the parent workbook is set accordingly.=== Debug Cells Formats
We can observe each cell format of a given excel file. Assume that we have an excel file like below:
|===
|Date
|12/31/2020 12.00 AM
|===
We can get all the list of cell formats using PoijiLogCellFormat
with PoijiOptions
:
PoijiLogCellFormat log = new PoijiLogCellFormat();
PoijiOptions options = PoijiOptions.PoijiOptionsBuilder.settings()
.poijiCellFormat(log)
.build();
List
Hmm, It looks like we did not achieve the correct date format since we get the date value as (12.00
). Let’s see how internally the excel file is being parsed via PoijiLogCellFormat
:
List
InternalCellFormat cell10 = formats.get(1);
Now that we know the reason of why we don’t see the expected date value, it’s because the default format of the date cell is the mm:ss.0
format with a given index 47, we need to change the default format of index (i.e. 47
). This format was automatically assigned to the cell having a number, but almost certainly with a special style or format. Note that this option should be used for debugging purpose only.
=== Modify Cells Formats
We can change the default format of a cell using PoijiNumberFormat
. Recall Debug Cells Formats
, we are unable to see the correct cell format, what’s more the excel file uses another format which we do not want to.
|===
|Date
|12/31/2020 12.00 AM
|===
Using PoijiNumberFormat
option, we are able to change the behavior of the format of a specific index:
PoijiNumberFormat numberFormat = new PoijiNumberFormat();
numberFormat.putNumberFormat((short) 47, “mm/dd/yyyy hh.mm aa”);
PoijiOptions options = PoijiOptions.PoijiOptionsBuilder.settings()
.poijiNumberFormat(numberFormat)
.build();
List
We know that the index 47 uses the format mm:ss.0
by default in the given excel file, thus we’re able to override its format with mm/dd/yyyy hh.mm aa
using the putNumberFormat
method.
=== Read Excel Properties
It is possible to read excel properties from xlsx files. To achieve that, create a class with fields annotated with @ExcelProperty
.
Example:
public class ExcelProperties {
@ExcelProperty
private String title;
@ExcelProperty
private String customProperty;
The field name corresponds to the name of the property inside the Excel file.
To use a different one than the field name, you can specify a propertyName
(e.g. @ExcelProperty(propertyName = "customPropertyName")
)
The list of built-in (e.g. non-custom) properties in an Excel file, which can be read by Poiji can be found in the class DefaultExcelProperties
.
Poiji can only read Text properties from an Excel file, so you have to use a String
to read them.
This does not apply to “modified”, “lastPrinted” and “created”, which are deserialized into a Date
.
=== Disable Cells Formats
Consider we have a xls or xlsx excel file like below:
|===
|Amount
|25,00
|(50,00)
|(65,00)
|===
Since we use a cell format on line 4 and 5 (i.e. (50,00)
and (65,00)
), we don’t want to see the formatted value of each cell after processing. In order to do that, we can use @DisableCellFormatXLS
on a field if the file ends with xls
or disableXLSXNumberCellFormat()
for xlsx files using PoijiOptions
.
public class TestInfo {
@ExcelCell(0)
private BigDecimal amount;
}
and let Poiji ignores the cell formats:
List
options
, if your excel is xlsx file.=== Create Custom Formatting
You can create your own formatting implementation without relying on the default Poiji formatting configuration using the Formatting
interface.
public class MyFormatting implements Formatting {
@Override
public String transform(PoijiOptions options, String value) {
return value.toUpperCase().trim(); <1>
}
}
public class Person {
@ExcelCellName("ID")
protected String employeeId;
@ExcelCellName("NAME")
protected String name;
@ExcelCellName("SURNAME")
protected String surname;
<1> Suppose that all the header names of an excel file have different formatting. Using custom formatting, we are able to look at headers with a custom format. All the headers will be uppercase and don’t have white spaces before and after.
Then you can add your custom implementation with the withFormatting
method:
=== Poi Sheet Support
Poiji accepts excel records via Poi Sheet object as well:
File file = new File(“/tmp/file.xlsx”);
FileInputStream fileInputStream = new FileInputStream(file);
Workbook workbook = new XSSFWorkbook(fileInputStream);
Sheet sheet = workbook.getSheetAt(0);
=== Update Default Locale
For parsing numbers and dates java.lang.Locale is used. Also Apache Poi uses the Locale for parsing.
As default, Poij uses Locale.US irrespective of Locale used on the running system. If you want to change that
you can use a option to pass the Locale to be used like shown below.
In this example the Jvm default locale is used. Beware that if your code run’s on a other Jvm with another Locale set as default parsing could give different results. Better is to use a fixed locale.
Also be aware of differences how Locales behave between Java 8 and 9+. For example AM/PM in Locale.GERMANY is displayed as AM/PM in Java 8 but Vorn./Nam. in Java 9 or higher.
This is due to the changes in Java 9. See https://openjdk.java.net/jeps/252[JEP-252] for more details.
== License
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